A Lighthouse Is Located on a Small Island $3 \mathrm {~km}$

question 16

Multiple Choice

A lighthouse is located on a small island, $3 \mathrm {~km}$ away from the nearest point $P$ on a straight shoreline, and its light makes four revolutions per minute. How fast is the beam of light moving along the shoreline when it is $1 \mathrm {~km}$ from $P$ ?

• A) \(1900 \pi \mathrm { km } / \mathrm { h }\)
• B) \(2000 \pi \mathrm { km } / \mathrm { h }\)
• C) \(1800 \pi \mathrm { km } / \mathrm { h }\)
• D) \(1700 \pi \mathrm { km } / \mathrm { h }\)
• E) \(1600 \pi \mathrm { km } / \mathrm { h }\)